George Doyle/Thinkstock(TOKYO) -- Tokyo has lodged a formal protest against Beijing after a Chinese warship aimed a radar used to direct missiles at a Japanese naval ship, reports The New York Times.

On Tuesday, Itsunori Onodera, Japan's defense minister, said the incident played out last Wednesday in the East China Sea, near disputed islands. And it wasn't the first time -- Tokyo said a Chinese ship also aimed the radar at a military helicopter earlier last month, according to the Times.

It's a significant escalation in a spat that began when Japan bought the disputed Senkaku islands, also claimed by Beijing.

The Chinese ship didn't fire in either incident, but Onodera said one misstep would've led to a "dangerous situation."